Дисертації з теми "Table contingence"
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1
Chah, Said. "Nouvelles techniques de codage d'association et de classification." Paris 6, 1986. http://www.theses.fr/1986PA066097.
Анотація:
La première partie de cette thèse est consacrée au problème de la recherche des partitions de e (ensemble à classifier) s'ajustant le mieux, au sens du critère de W. F. De la Vega, a la préordonnance p(s) induite sur e par un indice de similarité s. Dans la deuxième partie, on présente les bases d'une nouvelle théorie en classification automatique contenant la théorie classique des préordonnances comme cas particulier. Dans la troisième partie, on présente les principes de la théorie des "comparaisons par triplets" basée sur une nouvelle structure dite "triordonnance". La quatrième partie étudie un problème de structuration d'une table de contingence.
2
Jmel, Saïd. "Applications des modèles graphiques au choix de variables et à l'analyse des interactions dans une table de contingence multiple." Toulouse 3, 1992. http://www.theses.fr/1992TOU30091.
Анотація:
On presente quelques aspects de l'apport des modeles graphiques en analyse des donnees multidimensionnelles. Deux sujets ont ete abordes. Le premier concerne la selection des variables. On propose une nouvelle methode basee sur un type particulier de modeles graphiques. On donne deux applications de cette methode: la premiere en analyse en composantes principales et la seconde en analyse loglineaire. Le second sujet traite de la modelisation des interactions dans une table de contingence multiple. On montre comment l'analyse factorielle des correspondances et les modeles d'association ligne colonne de goodman peuvent sous certaines contraintes prendre en consideration la structure du graphe d'interactions ou le graphe d'independance conditionnelle associe a cette table. En complement, on suggere quelques techniques d'analyse des donnees susceptibles d'aider a la construction de tels graphes
3
Brink, Anton Meredith. "Bayesian analysis of contingency tables." Thesis, Imperial College London, 1997. http://hdl.handle.net/10044/1/8948.
4
Nguyên, Dominique Van. "Plausibilité et applications aux tables de contingence." Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb376000429.
5
Nguyen, Van Dominique. "Plausibilité et applications aux tables de contingence." Toulouse 3, 1986. http://www.theses.fr/1986TOU30100.
Анотація:
On rappelle la définition et les propriétés des systèmes de b-lods (chapitre 1) et de l'estimation exacte (chapitre 2) afin d'introduire la plausibilité comme une des généralisations de l'estimation exacte dans le cadre des systèmes de b-lods. Afin d'appliquer les résultats de la plausibilité conditionnelle à l'analyse des tables de contingence, on est amené à définir la classe des hypothèses log-linéaires homogènes (chapitre 3). On donne en exemple les programmes de calcul de l'estimation et de la valeur du test de rapport de plausibilité sous certaines hypothèses. Un niveau approximatif de ce test est déterminé à l'aide de simulations (chapitre 4)
6
Samusenko, Pavel. "Nonparametric criteria for sparse contingency tables." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2013. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2013~D_20130218_142205-74244.
Анотація:
In the dissertation, the problem of nonparametric testing for sparse contingency tables is addressed.
Statistical inference problems caused by sparsity of contingency tables are widely discussed in the literature. Traditionally, the expected (under null the hypothesis) frequency is required to exceed 5 in almost all cells of the contingency table. If this condition is violated, the χ2 approximations of goodness of fit statistics may be inaccurate and the table is said to be sparse . Several techniques have been proposed to tackle the problem: exact tests, alternative approximations, parametric and nonparametric bootstrap, Bayes approach and other methods. However they all are not applicable or have some limitations in nonparametric statistical inference of very sparse contingency tables.
In the dissertation, it is shown that, for sparse categorical data, the likelihood ratio statistic and Pearson’s χ2 statistic may become noninformative: they do not anymore measure the goodness-of-fit of null hypotheses to data. Thus, they can be inconsistent even in cases where a simple consistent test does exist.
An improvement of the classical criteria for sparse contingency tables is proposed. The improvement is achieved by grouping and smoothing of sparse categorical data by making use of a new sparse asymptotics model relying on (extended) empirical Bayes approach. Under general conditions, the consistency of the proposed criteria based on grouping is proved. Finite-sample behavior of... [to full text]Disertacijoje sprendžiami neparametrinių hipotezių tikrinimo uždaviniai išretintoms dažnių lentelėms. Problemos, susijusios su retų įvykių dažnių lentelėmis yra plačiai aptartos mokslinėje literatūroje. Yra pasiūlyta visa eilė metodų: tikslieji testai, alternatyvūs aproksimavimo būdai parametrinė ir neparametrinė saviranka, Bayeso ir kiti metodai. Tačiau jie nepritaikomi arba yra neefektyvūs neparametrinėje labai išretintų dažnių lentelių analizėje. Disertacijoje parodyta, kad labai išretintiems kategoriniams duomenims tikėtinumo santykio statistika ir Pearsono χ2 statistika gali pasidaryti neinformatyviomis: jos jau nėra tinkamos nulinės hipotezės ir duomenų suderinamumui matuoti. Vadinasi, jų pagrindu sudaryti kriterijai gali būti net nepagrįsti net tuo atveju, kai egzistuoja paprastas pagrįstas kriterijus. Darbe yra pasiūlytas klasikinių kriterijų patobulinimas išretintų dažnių lentelėms. Siūlomi kriterijai remiasi išretintų kategorinių duomenų grupavimu ir glodinimu naudojant naują išretinimo asimtotikos modelį, kuris remiasi (išplėstine) empirine Bayeso metodologija. Prie bendrų sąlygų yra įrodytas siūlomų kriterijų, naudojančių grupavimą, pagrįstumas. Kriterijų elgesys baigtinių imčių atveju tiriamas taikant Monte Carlo modeliavimą. Disertacija susideda iš įvado, 4 skyrių, literatūros sąrašo, bendrų išvadų ir priedo. Įvade atskleidžiama nagrinėjamos mokslinės problemos svarba, aprašomi darbo tikslai ir uždaviniai, tyrimo metodai, mokslinis naujumas, praktinė gautų... [toliau žr. visą tekstą]
7
Colas, Jo Ann. "Partition of the Chi-Squared Statistic in a Contingency Table." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/30352.
Анотація:
The Pearson statistic, a well-known goodness-of fit test in the analysis of contingency tables, gives little guidance as to why a null hypothesis is rejected. One approach to determine the source(s) of deviation from the null is the decomposition of a chi-squared statistic. This allows writing the statistic as the sum of independent chi-squared statistics.
First, three major types of contingency tables and the usual chi-squared tests are reviewed.
Three types of decompositions are presented and applied: one based on the partition of the
contingency table into independent subtables; one derived from smooth models and one from
the eigendecomposition of the central matrix defining the statistics. A comparison of some of the omnibus statistics decomposed above to a χ2(1)-distributed statistic shows that the omnibus statistics lack power compared to this statistic for testing hypothesis of equal success probabilities against monotonic trend in the success probabilities in a column-binomial contingency table.
8
Forster, Jonathan. "Models and marginal densities for multiway contingency tables." Thesis, University of Nottingham, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334557.
9
Michaelides, Danius Takis. "Exact tests via complete enumeration : a distributed computing approach." Thesis, University of Southampton, 1997. https://eprints.soton.ac.uk/250749/.
Анотація:
The analysis of categorical data often leads to the analysis of a contingency table. For large samples, asymptotic approximations are sufficient when calculating p-values, but for small samples the tests can be unreliable. In these situations an exact test should be considered. This bases the test on the exact distribution of the test statistic. Sampling techniques can be used to estimate the distribution. Alternatively, the distribution can be found by complete enumeration. A new algorithm is developed that enables a model to be defined by a model matrix, and all tables that satisfy the model are found. This provides a more efficient enumeration mechanism for complex models and extends the range of models that can be tested. The technique can lead to large calculations and a distributed version of the algorithm is developed that enables a number of machines to work efficiently on the same problem.
10
Yu, Yuan. "Tests of Independence in a Single 2x2 Contingency Table with Random Margins." Digital WPI, 2014. https://digitalcommons.wpi.edu/etd-theses/625.
Анотація:
In analysis of the contingency tables, the Fisher's exact test is a very important statistical significant test that is commonly used to test independence between the two variables. However, the Fisher' s exact test is based upon the assumption of the fixed margins. That is, the Fisher's exact test uses information beyond the table so that it is conservative. To solve this problem, we allow the margins to be random. This means that instead of fitting the count data to the hypergeometric distribution as in the Fisher's exact test, we model the margins and one cell using multinomial distribution, and then we use the likelihood ratio to test the hypothesis of independence. Furthermore, using Bayesian inference, we consider the Bayes factor as another test statistic. In order to judge the test performance, we compare the power of the likelihood ratio test, the Bayes factor test and the Fisher's exact test. In addition, we use our methodology to analyse data gathered from the Worcester Heart Attack Study to assess gender difference in the therapeutic management of patients with acute myocardial infarction (AMI) by selected demographic and clinical characteristics.
11
Khelladi, Mahieddine. "Analyse des tables de contingence : étude du problème de la contractilité." Grenoble 2, 1993. http://www.theses.fr/1993GRE21050.
Анотація:
Dans une table de contingence, l'elimination d'une ou plusieurs variables se fait en sommant le contenu des cases (effectif ou frequence) sur toutes ou certaines modalites de(s) variable(s) a eliminer, on obtient ainsi une table de contingence marginale ou contractee des variables restantes. Cette operation s'appelle contracter une table. Nous etudions en premier lieu, l'effet de contraction sur ce certaines structures d'association, le rapport des cotes et les parametres d'un modele log-lineaire. On distingue alors trois types de contractilite: la contractilite forte, la contractilite stricte et la pseud-contractilite. Ensuite nous developpons un test statistique conditionnel de contractilite dans les tables de contingence 2x2xk. Le procede est par suite generalise aux tables de contingence rxcxk proposant ainsi une solution a un probleme non encore completement resolu a notre connaissanceIn a contingency table, the elimination of one or several variables is one by summing the effet or frequencies of cells over all or some categories (modalities) of variables to be eliminated, we get then a marginal or collapsed contingency table of the remaining variables. This operation is called collapsing a table. We study first, the effect of collapsibility on some mesures of association, the odds ratio and the parameters of log-linear models. We distinguish then between three types of collapsibility : the strong collapsibility, the strict collapsibility and the pseudo-collapsibility. Then, we developp a conditional test statistic of collapsibility in 2x2xk contingency tables. The process is then generalised to rxcxk contingency tables. We give thus a solution to a problem not completely solved to our knowledge
12
Meyer, David, Achim Zeileis, and Kurt Hornik. "The Strucplot Framework: Visualizing Multi-way Contingency Tables with vcd." Department of Statistics and Mathematics, WU Vienna University of Economics and Business, 2005. http://epub.wu.ac.at/480/1/document.pdf.
Анотація:
This paper describes the `strucplot' framework for the visualization of multi-way contingency tables. Strucplot displays include hierarchical conditional plots such as mosaic, association, and sieve plots, and can be combined into more complex, specialized plots for visualizing conditional independence, GLMs, and the results of independence tests. The framework's modular design allows flexible customization of the plots' graphical appearance, including shading, labeling, spacing, and legend, by means of graphical appearance control (`grapcon') functions. The framework is provided by the R package vcd. (author's abstract)Series: Research Report Series / Department of Statistics and Mathematics
13
Hornik, Kurt, Achim Zeileis, and David Meyer. "The Strucplot Framework: Visualizing Multi-way Contingency Tables with vcd." American Statistical Association, 2006. http://epub.wu.ac.at/3984/1/strucplot.pdf.
Анотація:
This paper describes the "strucplot" framework for the visualization of multi-way contingency
tables. Strucplot displays include hierarchical conditional plots such as mosaic,
association, and sieve plots, and can be combined into more complex, specialized plots for
visualizing conditional independence, GLMs, and the results of independence tests. The
framework's modular design allows flexible customization of the plots' graphical appearance,
including shading, labeling, spacing, and legend, by means of "graphical appearance
control" functions. The framework is provided by the R package vcd.
14
Ait, Sidi Allal Moulay Lahcen. "Contributions à l'étude des modèles d'association dans l'analyse des tables de contingence." Toulouse 3, 1996. http://www.theses.fr/1996TOU30011.
Анотація:
Dans ce travail, nous nous sommes interesses a deux problemes relatifs au modele d'association: la distribution asymptotique des estimateurs maximum de vraisemblance (emv) et le choix de la dimension. La premiere partie est consacree a la determination de la matrice des co variances asymptotiques des emv dans le modele d'association, ainsi que dans d'autres modeles voisins. La deuxieme partie passe en revue differents criteres de choix de la dimension optimale d'un modele. Nous nous sommes plus particulierement interesses dans cette partie a deux criteres relativement recents icomp et icompifim. A chaque fois, plusieurs illustrations ont ete proposees
15
Johnson, Justin Scott Escobar Martha Cecilia. "Initially held hypothesis does not affect encoding of event frequencies in contingency based causal judgment." Auburn, Ala., 2009. http://hdl.handle.net/10415/1948.
16
Kim, Seoung Bum. "Data Mining in Tree-Based Models and Large-Scale Contingency Tables." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/6825.
Анотація:
This thesis is composed of two parts. The first part pertains to tree-based models. The second part deals with multiple testing in large-scale contingency tables. Tree-based models have gained enormous popularity in statistical modeling and data mining. We propose a novel tree-pruning algorithm called frontier-based tree-pruning algorithm (FBP). The new method has an order of computational complexity comparable to cost-complexity pruning (CCP). Regarding tree pruning, it provides a full spectrum of information. Numerical study on real data sets reveals a surprise: in the complexity-penalization approach, most of the tree sizes are inadmissible. FBP facilitates a more faithful implementation of cross validation, which is favored by simulations.
One of the most common test procedures using two-way contingency tables is the test of independence between two categorizations. Current test procedures such as chi-square or likelihood ratio tests provide overall independency but bring limited information about the nature of the association in contingency tables. We propose an approach of testing independence of categories in individual cells of contingency tables based on a multiple testing framework. We then employ the proposed method to identify the patterns of pair-wise associations between amino acids involved in beta-sheet bridges of proteins. We identify a number of amino acid pairs that exhibit either strong or weak association. These patterns provide useful information for algorithms that predict secondary and tertiary structures of proteins.
17
Khedri, Shiler. "Markov chain Monte Carlo methods for exact tests in contingency tables." Thesis, Durham University, 2012. http://etheses.dur.ac.uk/5579/.
Анотація:
This thesis is mainly concerned with conditional inference for contingency tables, where the MCMC method is used to take a sample of the conditional distribution. One of the most common models to be investigated in contingency tables is the independence model. Classic test statistics for testing the independence hypothesis, Pearson and likelihood chi-square statistics rely on large sample distributions. The large sample distribution does not provide a good approximation when the sample size is small. The Fisher exact test is an alternative method which enables us to compute the exact p-value for testing the independence hypothesis. For contingency tables of large dimension, the Fisher exact test is not practical as it requires counting all tables in the sample space. We will review some enumeration methods which do not require us to count all tables in the sample space. However, these methods would also fail to compute the exact p-value for contingency tables of large dimensions. \cite{DiacStur98} introduced a method based on the Grobner basis. It is quite complicated to compute the Grobner basis for contingency tables as it is different for each individual table, not only for different sizes of table. We also review the method introduced by \citet{AokiTake03} using the minimal Markov basis for some particular tables. \cite{BuneBesa00} provided an algorithm using the most fundamental move to make the irreducible Markov chain over the sample space, defining an extra space. The algorithm is only introduced for $2\times J \times K$ tables using the Rasch model. We introduce direct proof for irreducibility of the Markov chain achieved by the Bunea and Besag algorithm. This is then used to prove that \cite{BuneBesa00} approach can be applied for some tables of higher dimensions, such as $3\times 3\times K$ and $3\times 4 \times 4$. The efficiency of the Bunea and Besag approach is extensively investigated for many different settings such as for tables of low/moderate/large dimensions, tables with special zero pattern, etc. The efficiency of algorithms is measured based on the effective sample size of the MCMC sample. We use two different metrics to penalise the effective sample size: running time of the algorithm and total number of bits used. These measures are also used to compute the efficiency of an adjustment of the Bunea and Besag algorithm which show that it outperforms the the original algorithm for some settings.
18
Ye, Ping. "Tests of symmetry with ordered alternatives in three-dimensional contingency tables /." Available to subscribers only, 2008. http://proquest.umi.com/pqdweb?did=1594480501&sid=17&Fmt=2&clientId=1509&RQT=309&VName=PQD.
19
Messatfa, Hammou. "Unification relationnelle des criteres et structures optimales des tables de contingences." Paris 6, 1990. http://www.theses.fr/1990PA066241.
Анотація:
La premiere partie de notre these developpe une approche unificatrice et interpretative de plusieurs mesures d'association proposees dans la litterature. Nous utilisons les comparaisons par paires et quelques techniques de normalisation pour mettre en evidence les relations entre ces differentes mesures. Dans une deuxieme partie, nous abordons des problemes de structures optimales de tables de contingence: 1) nous montrons comment approximer la somme des carres d'une table de contingence a marge fixee. Nous examinons quelques approches deja etudiees et nous proposons: 1) une heuristique basee sur des techniques d'affectation, 2) une heuristique derivant d'un probleme de transport. Ces deux procedures ont ete appliquees au probleme de partitionnement de graphes: 1) nous resolvons le probleme de l'estimation d'une table de contingence a marges fixees, a partir d'une seconde table donnee, tout en conservant une certaine structure
20
Mesbah, Mounir. "Estimation et tests dans les tables de contingence mixtes en présence d'erreurs de mesure." Paris 5, 1992. http://www.theses.fr/1992PA05S015.
Анотація:
Le chapitre 1 de cette thèse porte sur la construction des distributions conditionnellement gaussiennes. Dans le chapitre 2, nous présentons des résultats sur l'effet des erreurs de mesures sur les estimations et les tests dans les tables de contingence mixtes. Nous montrons qu'en présence de certaines indépendances conditionnelles particulières, l'association entre variables est soit toujours diminuée, soit toujours augmentée. Néanmoins dans certains cas les tests d'indépendance restent de niveau correct. Leur puissance est, pour certains types de modèles, toujours diminuée. Nous caractérisons ensuite la classe des modèles graphiques invariants par erreurs de type Korn. Le chapitre 3 porte sur la correction des erreurs de mesure, si l'on dispose d'un deuxième échantillon, ou l'on observe conjointement la variable mesurée correctement et sa version erronée. Une méthode générale consiste à construire une table de contingence partiellement observée croisant l'ensemble des variables des deux échantillons et à estimer ces effectifs à l'aide d'un modèle conditionnellement gaussiens particulier. Le chapitre 4 porte sur le choix de ce modèle. Nous montrons que certains de ces modèles sont incompatibles avec les observations et nous donnons des règles simples pour les déterminer
21
Yenigun, Deniz C. "A Test of Independence in Two-Way Contingency Tables Based on Maximal Correlation." Bowling Green State University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1182286318.
22
Pan, Xuemei. "Factors influencing the mixture index of model fit in contingency tables showing indenpendence." College Park, Md. : University of Maryland, 2006. http://hdl.handle.net/1903/4101.
Анотація:
Thesis (Ph. D.) -- University of Maryland, College Park, 2006.Thesis research directed by: Measurement, Statistics and Evaluation. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
23
Espendiller, Michael [Verfasser], Maria [Akademischer Betreuer] Kateri, and Udo [Akademischer Betreuer] Kamps. "Association in contingency tables : an informationtheoretic approach / Michael Espendiller ; Maria Kateri, Udo Kamps." Aachen : Universitätsbibliothek der RWTH Aachen, 2017. http://d-nb.info/1158599560/34.
24
Bhatta, Dilli. "A Bayesian Test of Independence for Two-way Contingency Tables Under Cluster Sampling." Digital WPI, 2013. https://digitalcommons.wpi.edu/etd-dissertations/128.
Анотація:
We consider a Bayesian approach to the study of independence in a two-way contingency table obtained from a two-stage cluster sampling design. We study the association between two categorical variables when (a) there are no covariates and (b) there are covariates at both unit and cluster levels. Our main idea for the Bayesian test of independence is to convert the cluster sample into an equivalent simple random sample which provides a surrogate of the original sample. Then, this surrogate sample is used to compute the Bayes factor to make an inference about independence. For the test of independence without covariates, the Rao-Scott corrections to the standard chi-squared (or likelihood ratio) statistic were developed. They are ``large sample' methods and provide appropriate inference when there are large cell counts. However, they are less successful when there are small cell counts. We have developed the methodology to overcome the limitations of Rao-Scott correction. We have used a hierarchical Bayesian model to convert the observed cluster samples to simple random samples. This provides the surrogate samples which can be used to derive the distribution of the Bayes factor to make an inference about independence. We have used a sampling-based method to fit the model. For the test of independence with covariates, we first convert the cluster sample with covariates to a cluster sample without covariates. We use multinomial logistic regression model with random effects to accommodate the cluster effects. Our idea is to fit the cluster samples to the random effect models and predict the new samples by adjusting with the covariates. This provides the cluster sample without covariates. We then use a hierarchical Bayesian model to convert this cluster sample to a simple random sample which allows us to calculate the Bayes factor to make an inference about independence. We use Markov chain Monte Carlo methods to fit our models. We apply our first method to the Third International Mathematics and Science Study (1995) for third grade U.S. students in which we study the association between the mathematics test scores and the communities the students come from, and science test scores and the communities the students come from. We also provide a simulation study which establishes our methodology as a viable alternative to the Rao-Scott approximations for relatively small two-stage cluster samples. We apply our second method to the data from the Trend in International Mathematics and Science Study (2007) for fourth grade U.S. students to assess the association between the mathematics and science scores represented as categorical variables and also provide the simulation study. The result shows that if there is strong association between two categorical variables, there is no difference between the significance of the test in using the model (a) with covariates and (b) without covariates. However, in simulation studies, there is a noticeable difference in the significance of the test between the two models when there are borderline cases (i.e., situations where there is marginal significance).
25
Basak, Tapati. "A Geometry-Based Multiple Testing Correction for Contingency Tables by Truncated Normal Distribution." Doctoral thesis, Kyoto University, 2021. http://hdl.handle.net/2433/264648.
Анотація:
京都大学新制・課程博士
博士(医学)
甲第23367号
医博第4736号
新制||医||1051(附属図書館)
京都大学大学院医学研究科医学専攻
(主査)教授 森田 智視, 教授 川上 浩司, 教授 佐藤 俊哉
学位規則第4条第1項該当
Doctor of Medical Science
Kyoto University
DFAM
26
Ganajová, Michaela. "Aplikace korespondenční analýzy v programu MS Excel." Master's thesis, Vysoká škola ekonomická v Praze, 2008. http://www.nusl.cz/ntk/nusl-15778.
Анотація:
The aim of the diploma thesis was to create independently an application, automating a correspondence analysis calculation using MS Excel and taking advantage of VBA programming language. The application was then used to analyse Slovak banking sector. The created application is based on macro sets which can be split up to two parts. The first part produces a contingency table and converts it into a format usable in the second part. Then there is executed the Correspondence Analysis calculation itself. Supplement Matrix is being used, that allows to discharge functions from matrix and linear algebra. The application allows to process any matrix dimension. Dialog window offers four normalization types, shortened and also full output and it is possible to display row or column variable categories, eventually both. The analysis subject was to find out which of the products are typical for considered banks and for which clients, divided into age categories, is attractive particular bank and/or product. A starting point is a product usage data matrix at a particular bank. There was made a conclusion, that it is possible to divide banks into more traditional or modern type institutions and also that each bank has a typical product.
27
Amiri, Saeid. "On the Application of the Bootstrap : Coefficient of Variation, Contingency Table, Information Theory and Ranked Set Sampling." Doctoral thesis, Uppsala universitet, Matematiska institutionen, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-159206.
Анотація:
This thesis deals with the bootstrap method. Three decades after the seminal paper by Bradly Efron, still the horizons of this method need more exploration. The research presented herein has stepped into different fields of statistics where the bootstrap method can be utilized as a fundamental statistical tool in almost any application. The thesis considers various statistical problems, which is explained briefly below. Bootstrap method: A comparison of the parametric and the nonparametric bootstrap of variance is presented. The bootstrap of ranked set sampling is dealt with, as well as the wealth of theories and applications on the RSS bootstrap that exist nowadays. Moreover, the performance of RSS in resampling is explored. Furthermore, the application of the bootstrap method in the inference of contingency table test is studied. Coefficient of variation: This part shows the capacity of the bootstrap for inferring the coefficient of variation, a task which the asymptotic method does not perform very well. Information theory: There are few works on the study of information theory, especially on the inference of entropy. The papers included in this thesis try to achieve the inference of entropy using the bootstrap method.
28
Xi, Jing. "Polytopes Arising from Binary Multi-way Contingency Tables and Characteristic Imsets for Bayesian Networks." UKnowledge, 2013. http://uknowledge.uky.edu/statistics_etds/5.
Анотація:
The main theme of this dissertation is the study of polytopes arising from binary multi-way contingency tables and characteristic imsets for Bayesian networks.
Firstly, we study on three-way tables whose entries are independent Bernoulli ran- dom variables with canonical parameters under no three-way interaction generalized linear models. Here, we use the sequential importance sampling (SIS) method with the conditional Poisson (CP) distribution to sample binary three-way tables with the sufficient statistics, i.e., all two-way marginal sums, fixed. Compared with Monte Carlo Markov Chain (MCMC) approach with a Markov basis (MB), SIS procedure has the advantage that it does not require expensive or prohibitive pre-computations. Note that this problem can also be considered as estimating the number of lattice points inside the polytope defined by the zero-one and two-way marginal constraints. The theorems in Chapter 2 give the parameters for the CP distribution on each column when it is sampled. In this chapter, we also present the algorithms, the simulation results, and the results for Samson’s monks data.
Bayesian networks, a part of the family of probabilistic graphical models, are widely applied in many areas and much work has been done in model selections for Bayesian networks. The second part of this dissertation investigates the problem of finding the optimal graph by using characteristic imsets, where characteristic imsets are defined as 0-1 vector representations of Bayesian networks which are unique up to Markov equivalence. Characteristic imset polytopes are defined as the convex hull of all characteristic imsets we consider. It was proven that the problem of finding optimal Bayesian network for a specific dataset can be converted to a linear programming problem over the characteristic imset polytope [51]. In Chapter 3, we first consider characteristic imset polytopes for all diagnosis models and show that these polytopes are direct product of simplices. Then we give the combinatorial description of all edges and all facets of these polytopes. At the end of this chapter, we generalize these results to the characteristic imset polytopes for all Bayesian networks with a fixed underlying ordering of nodes.
Chapter 4 includes discussion and future work on these two topics.
29
Tadepalli, Sriram Satish. "Schemas of Clustering." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/26261.
Анотація:
Data mining techniques, such as clustering, have become a mainstay in many applications such as bioinformatics, geographic information systems, and marketing. Over the last decade, due to new demands posed by these applications, clustering techniques have been significantly adapted and extended. One such extension is the idea of finding clusters in a dataset that preserve information about some auxiliary variable. These approaches tend to guide the clustering algorithms that are traditionally unsupervised learning techniques with the background knowledge of the auxiliary variable. The auxiliary information could be some prior class label attached to the data samples or it could be the relations between data samples across different datasets. In this dissertation, we consider the latter problem of simultaneously clustering several vector valued datasets by taking into account the relationships between the data samples.
We formulate objective functions that can be used to find clusters that are local in each individual dataset and at the same time maximally similar or dissimilar with respect to clusters across datasets. We introduce diverse applications of these clustering algorithms: (1) time series segmentation (2) reconstructing temporal models from time series segmentations (3) simultaneously clustering several datasets according to database schemas using a multi-criteria optimization and (4) clustering datasets with many-many relationships between data samples.
For each of the above, we demonstrate applications, including modeling the yeast cell cycle and the yeast metabolic cycle, understanding the temporal relationships between yeast biological processes, and cross-genomic studies involving multiple organisms and multiple stresses. The key contribution is to structure the design of complex clustering algorithms over a database schema in terms of clustering algorithms over the underlying entity sets.Ph. D.
30
Kraus, Katrin. "On the Measurement of Model Fit for Sparse Categorical Data." Doctoral thesis, Uppsala universitet, Statistiska institutionen, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-173768.
Анотація:
This thesis consists of four papers that deal with several aspects of the measurement of model fit for categorical data. In all papers, special attention is paid to situations with sparse data. The first paper concerns the computational burden of calculating Pearson's goodness-of-fit statistic for situations where many response patterns have observed frequencies that equal zero. A simple solution is presented that allows for the computation of the total value of Pearson's goodness-of-fit statistic when the expected frequencies of response patterns with observed frequencies of zero are unknown. In the second paper, a new fit statistic is presented that is a modification of Pearson's statistic but that is not adversely affected by response patterns with very small expected frequencies. It is shown that the new statistic is asymptotically equivalent to Pearson's goodness-of-fit statistic and hence, asymptotically chi-square distributed. In the third paper, comprehensive simulation studies are conducted that compare seven asymptotically equivalent fit statistics, including the new statistic. Situations that are considered concern both multinomial sampling and factor analysis. Tests for the goodness-of-fit are conducted by means of the asymptotic and the bootstrap approach both under the null hypothesis and when there is a certain degree of misfit in the data. Results indicate that recommendations on the use of a fit statistic can be dependent on the investigated situation and on the purpose of the model test. Power varies substantially between the fit statistics and the cause of the misfit of the model. Findings indicate further that the new statistic proposed in this thesis shows rather stable results and compared to the other fit statistics, no disadvantageous characteristics of the fit statistic are found. Finally, in the fourth paper, the potential necessity of determining the goodness-of-fit by two sided model testing is adverted. A simulation study is conducted that investigates differences between the one sided and the two sided approach of model testing. Situations are identified for which two sided model testing has advantages over the one sided approach.
31
Ma, Baofu. "Analyzing the Combination of Polymorphisms Associating with Antidepressant Response by Exact Conditional Test." Digital Archive @ GSU, 2005. http://digitalarchive.gsu.edu/math_theses/2.
Анотація:
Genetic factors have been shown to be involved in etiology of a poor response to the antidepressant treatment with sufficient dosage and duration. Our goal was to identify the role of polymorphisms in the poor response to the treatment. To this end, 5 functional polymorphisms in 109 patients diagnosed with unipolar, major depressive disorder are analyzed. Due to the small sample size, exact conditional tests are utilized to analyze the contingency table. The data analysis involves: (1) Exact test for conditional independence in a high dimensional contingency table; (2) Marginal independence test; (3) Exact test for three-way interactions. The efficiency of program always limits the application of exact test. The appropriate methods for enumerating exact tables are the key to improve the efficiency of programs. The algorithm of enumerating the exact tables is also introduced.
32
Lee, Juyoun Slavkovic Aleksandra B. "Sampling contingency tables given sets of marginals and/or conditionals in the context of statistical disclosure limitation." [University Park, Pa.] : Pennsylvania State University, 2009. http://etda.libraries.psu.edu/theses/approved/WorldWideIndex/ETD-4572/index.html.
33
Popovic, Ray. "Parameter estimation error: a cautionary tale in computational finance." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34731.
Анотація:
We quantify the effects on contingent claim valuation of using an estimator for the volatility of a geometric Brownian motion (GBM) process. That is, we show what difficulties can arise when failing to account for estimation risk. Our working problem uses a direct estimator of volatility based on the sample standard deviation of increments from the underlying Brownian motion. After substituting into the GBM the direct volatility estimator for the true, but unknown, value of the parameter sigma, we derive the resulting marginal distribution of the approximated GBM. This allows us to derive post-estimation distributions and valuation formulae for an assortment of European contingent claims that are in accord with the basic properties of the underlying risk-neutral process.
Next we extend our work to the contingent claim sensitivities associated with an assortment of European option portfolios that are based on the direct estimator of the volatility of the GBM process. Our approach to the option sensitivities - the Greeks - uses the likelihood function technique. This allows us to obtain computable results for the technically more-complicated formulae associated with our post-estimation process. We discuss an assortment of difficulties that can ensue when failing to account for estimation risk in valuation and hedging formulae.
34
Pereira, Gislaine Rocha. "Uma revisão sobre o uso analítico de dados provenientes de amostras com estruturas complexas." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/11/11134/tde-28112016-144856/.
Анотація:
Neste trabalho foi realizada uma revisão bibliográfica acerca das metodologias encontradas na literatura de como são aplicados os métodos para o uso analítico de dados provenientes de pesquisas que envolvem esquemas amostrais complexos. Objetivou-se mostrar e discutir alguns estudos que avaliam o impacto de ignorar o plano amostral na análise dos dados. Foi feito também um levantamento de artigos com o objetivo de fazer um estudo de trabalhos publicados em jornais, revistas ou periódicos, cujos assuntos abordados tratam da incorporação da estrutura complexa da amostra na análise. Essa revisão evidenciou que os métodos clássicos de análise, ou seja, aqueles que supõem que os dados provém de uma amostragem aleatória simples, podem levar a resultados incorretos produzindo conclusões errôneas ou equivocadas quando os dados provém de esquemas amostrais complexos.This work was carried out a literature review about the methodologies found in the literature of how the methods for data analytical use from research involving complex sampling schemes are applied. It was aimed to show and discuss some studies that assess the impact of ignoring the sampling scheme in the data analysis. It was also made a survey of articles in order to make a study of works published in newspapers, magazines or periodicals, which addressed issues dealing with the incorporation of the complex structure of the sample in the analysis. This review shown that the classical methods of analysis, i.e. those who assume that the data comes from a simple random sampling can lead to incorrect results producing quite erroneous and misleading conclusions when the data come from complex sample schemes.
35
Whistler, James W. "ANALYSIS OF EMBRYO SCORING AND COMPARISON OF CLINIC PERFORMANCE IN IN-VITRO FERTILIZATION." DigitalCommons@CalPoly, 2015. https://digitalcommons.calpoly.edu/theses/1376.
Анотація:
Clinical Assisted Reproductive Technology (ART) practices seek to make improvements in embryo quality and resultant procedural success rates. There is a significant variance in live birth rates among clinics nationwide. The goal of this thesis is make comparisons of embryo quality among clinics and understand these differences. This analysis focuses on the stage between egg retrieval and embryo transfer. Because the currently accepted embryo scoring methods are not directly proportional to performance, a new scoring methodology is proposed and applied. Data provided by the Society for Assisted Reproductive Technology (SART) consisting of 36,836 patient cycles from 40 anonymous clinics nationwide is considered. After necessary reductions are made, the data is anatomized to link each embryo transferred to an implantation probability. A score is generated for each morphology grouping based on the average implantation rate of that group. This score is used as the basis for clinic comparisons. Top-performing clinics (in terms of live birth rates in patients agedold) are then shown to both produce embryos of higher score and achieve better results from embryos of identical morphology.
36
Zeileis, Achim, David Meyer, and Kurt Hornik. "Residual-based shadings for visualizing (conditional) independence." Department of Statistics and Mathematics, WU Vienna University of Economics and Business, 2005. http://epub.wu.ac.at/1122/1/document.pdf.
Анотація:
Residual-based shadings for enhancing mosaic and association plots to visualize independence models for contingency tables are extended in two directions: (a) perceptually uniform HCL colors are used and (b) the result of an associated significance test is coded by the appearance of color in the visualization. For obtaining (a), a general strategy for deriving diverging palettes in the perceptually-based HCL space is suggested. As for (b), cut offs that control the appearance of color are computed in a data-driven way based on the conditional permutation distribution of maximum-type test statistics. The shadings are first established for the case of independence in 2-way tables and then extended to more general independence models for multi-way tables, including in particular conditional independence problems.Series: Research Report Series / Department of Statistics and Mathematics
37
Mullen, Jerry D. (Jerry Davis). "A Comparison of Some Continuity Corrections for the Chi-Squared Test in 3 x 3, 3 x 4, and 3 x 5 Tables." Thesis, North Texas State University, 1987. https://digital.library.unt.edu/ark:/67531/metadc331001/.
Анотація:
This study was designed to determine whether chis-quared based tests for independence give reliable estimates (as compared to the exact values provided by Fisher's exact probabilities test) of the probability of a relationship between the variables in 3 X 3, 3 X 4 , and 3 X 5 contingency tables when the sample size is 10, 20, or 30. In addition to the classical (uncorrected) chi-squared test, four methods for continuity correction were compared to Fisher's exact probabilities test. The four methods were Yates' correction, two corrections attributed to Cochran, and Mantel's correction. The study was modeled after a similar comparison conducted on 2 X 2 contingency tables and published by Michael Haber.
38
Pemmanaboina, Rajashekar. "Assessing Crash Occurrence On Urban Freeways Using Static And Dynamic Factors By Applying A System Of Interrelated Equations." Master's thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2617.
Анотація:
Traffic crashes have been identified as one of the main causes of death in the US, making road safety a high priority issue that needs urgent attention. Recognizing the fact that more and effective research has to be done in this area, this thesis aims mainly at developing different statistical models related to the road safety. The thesis includes three main sections: 1) overall crash frequency analysis using negative binomial models, 2) seemingly unrelated negative binomial (SUNB) models for different categories of crashes divided based on type of crash, or condition in which they occur, 3) safety models to determine the probability of crash occurrence, including a rainfall index that has been estimated using a logistic regression model. The study corridor is a 36.25 mile stretch of Interstate 4 in Central Florida. For the first two sections, crash cases from 1999 through 2002 were considered. Conventionally most of the crash frequency analysis model all crashes, instead of dividing them based on type of crash, peaking conditions, availability of light, severity, or pavement condition, etc. Also researchers traditionally used AADT to represent traffic volumes in their models. These two cases are examples of macroscopic crash frequency modeling. To investigate the microscopic models, and to identify the significant factors related to crash occurrence, a preliminary study (first analysis) explored the use of microscopic traffic volumes related to crash occurrence by comparing AADT/VMT with five to twenty minute volumes immediately preceding the crash. It was found that the volumes just before the time of crash occurrence proved to be a better predictor of crash frequency than AADT. The results also showed that road curvature, median type, number of lanes, pavement surface type and presence of on/off-ramps are among the significant factors that contribute to crash occurrence. In the second analysis various possible crash categories were prepared to exactly identify the factors related to them, using various roadway, geometric, and microscopic traffic variables. Five different categories are prepared based on a common platform, e.g. type of crash. They are: 1) Multiple and Single vehicle crashes, 2) Peak and Off-peak crashes, 3) Dry and Wet pavement crashes, 4) Daytime and Dark hour crashes, and 5) Property Damage Only (PDO) and Injury crashes. Each of the above mentioned models in each category are estimated separately. To account for the correlation between the disturbance terms arising from omitted variables between any two models in a category, seemingly unrelated negative binomial (SUNB) regression was used, and then the models in each category were estimated simultaneously. SUNB estimation proved to be advantageous for two categories: Category 1, and Category 4. Road curvature and presence of On-ramps/Off-ramps were found to be the important factors, which can be related to every crash category. AADT was also found to be significant in all the models except for the single vehicle crash model. Median type and pavement surface type were among the other important factors causing crashes. It can be stated that the group of factors found in the model considering all crashes is a superset of the factors that were found in individual crash categories. The third analysis dealt with the development of a logistic regression model to obtain the weather condition at a given time and location on I-4 in Central Florida so that this information can be used in traffic safety analyses, because of the lack of weather monitoring stations in the study area. To prove the worthiness of the weather information obtained form the analysis, the same weather information was used in a safety model developed by Abdel-Aty et al., 2004. It was also proved that the inclusion of weather information actually improved the safety model with better prediction accuracy.M.S.C.E.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Civil Engineering
39
Šulc, Zdeněk. "Metody analýzy vícerozměrných kontingenčních tabulek." Master's thesis, Vysoká škola ekonomická v Praze, 2011. http://www.nusl.cz/ntk/nusl-114292.
Анотація:
This thesis occupies with a relationship of two significant methods of analyzing multivariate contingency tables, namely correspondence analysis and loglinear models. The thesis is divided into three parts. The first one is dedicated to basic terms of categorical data analysis, mainly to contingency tables and their distributions. Primarily, the emphasis is placed on their multidimensional form. The second part presents tools and techniques of both methods in a scope needed for their practical use and interpretation of their results. A practical application of both methods is included in the third part which is presented on the data from a market research. This part describes settings for both analyses in a statistical software SPSS and the subsequent interpretation of their outputs. A comparison of analyzed methods in terms of their use can be found in the conclusion.
40
Cafourková, Magdalena. "Zkoumání závislosti materiální deprivace domácností ČR na vybraných faktorech." Master's thesis, Vysoká škola ekonomická v Praze, 2012. http://www.nusl.cz/ntk/nusl-165094.
Анотація:
The aim of this thesis is to analyse the material deprivation of the households with regard to the selected indicators, i.e. the costs that the household spends on housing, a region where the household is located, the number of the members and the dependent children in the household, age and sex of a head of the household, and economic activity and education level of the members of the household. The thesis aims not only to prove the dependence among the selected indicators but also to quantify this dependence by using the odds ratio. The individual effect of all variables was proven except of the one related to the number of the dependent children. It was also demonstrated that the factors constituting a threat for the households by a material deprivation rate vary by the different age groups. However, it can be concluded that across all the age groups, the material deprivation rate is determined by the sex of a head of the household, education level of the members of the household, and the costs that the household spends on housing.
41
Steinfeld, Uwe H. "Draftsmans displays for contingency tables using a full-screen, scrollable APL2 spreadsheet input/output editor with application to the PERSEREC database of Special Background Investigation." Thesis, Monterey, California. Naval Postgraduate School, 1990. http://hdl.handle.net/10945/37552.
Анотація:
Approved for public release, distribution is unlimited.A full-screen, scrollable spreadsheet-like editor written in the APL2 language is described for inputting, examining and outputting data. Mixed numeric and character arrays can be read into or read out to formatted DOS files (ASCII) or comma delimited DOS files. Alternatively a bulk mode input facility allows for rapid direct data entry, or data can be examined and edited cell-by-cell in the usual way. Columns, rows or blocks of data can be highlighted in a chosen color, shadowed, moved or copied. In addition APL functions entered on the command line can use the blocks as input or output. A facility for coding missing values is also provided. Major-to-minor (lexicographic) sorts can be performed on selected columns, and conditional or unconditional frequency tabulations and cross-tabulations of selected columns can be performed. Output is obtained as a new spreadsheet, or equivalently, as an APL2 matrix. In particular, two-way cross-tabulations of multiple columns are laid out in the spreadsheet like draftsman plots to facilitate investigation and explanation of multivariate categorical data. No numerical coding of the data is needed.
42
Vlach, Petr. "Grafický podsystém v prostředí internetového prohlížeče." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2008. http://www.nusl.cz/ntk/nusl-235437.
Анотація:
This master's thesis, divided into two sections, compares in part one existing (non-)commercial systems for OLAP presentation using contingency table or graph. The main focus is put on a graph. Results received from my observations in part one are used for implementing a graphic subsystem within internet browser's environment. User friendly interface and good arrangement of displayed data are the most important tasks.
43
Chen, Dandan. "Amended Estimators of Several Ratios for Categorical Data." Digital Commons @ East Tennessee State University, 2006. https://dc.etsu.edu/etd/2218.
Анотація:
Point estimation of several association parameters in categorical data are presented. Typically, a constant is added to the frequency counts before the association measure is computed. We will study the accuracy of these adjusted point estimators based on frequentist and Bayesian methods respectively. In particular, amended estimators for the ratio of independent Poisson rates, relative risk, odds ratio, and the ratio of marginal binomial proportions will be examined in terms of bias and mean squared error.
44
Konrádová, Lucie. "Korespondenční analýza." Master's thesis, Vysoká škola ekonomická v Praze, 2006. http://www.nusl.cz/ntk/nusl-10408.
Анотація:
The aim of this thesis is to introduce statistical method called Correspondence analysis as a strong instrument for exploratory data analysis. The main purpose is to understand how to interpret the correspondence map, the graphical output of this method, correctly. The method is presented both in its simple version, and its extension to multivariate data. Usage of method is demonstrated on data of non-financial subjects of Czech republic, which are entered in the register of economic subjects.
45
Mašková, Jana. "Analýza dat ze závislých výběrů ve výzkumu trhu." Master's thesis, Vysoká škola ekonomická v Praze, 2008. http://www.nusl.cz/ntk/nusl-19243.
Анотація:
There are surveys carried out repeatedly on the same set of units. In connection with such research, we are talking about the dependent samples. The aim and the contribution of this diploma thesis is a summary of available methods for analyzing data from dependent samples for both continuous and discrete variables. The Czech literature has been devoted to this topic only marginally. The theoretical part is divided into two main parts for two waves and for more waves of exploration, which are further divided according to the type of reference variable. The third part is devoted to the application of the theoretical information in a market research.
46
Fonseca, Cristina Moreira. "Contingência e contigüidade no responder de ratos submetidos a esquemas de razão e intervalo variáveis." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/47/47132/tde-25092006-005520/.
Анотація:
O presente estudo é formado por dois experimentos (Experimento 1 e Experimento 2) que empregaram procedimento de atraso de reforço não sinalizado non-resetting [esquema tandem em que o segundo componente ocorre em tempo fixo (FT)]. Os experimentos tiveram como objetivo geral manipular experimentalmente relações de contingência e contigüidade utilizando diferentes esquemas de reforço (esquema dependente de resposta, esquema dependente da resposta com liberação atrasada do reforço e esquema independente de resposta). Mais especificamente, os experimentos tiveram como objetivo verificar os efeitos produzidos pela introdução do atraso do reforço sobre a taxa e a distribuição de freqüência no tempo das respostas de pressão à barra, emitidas por ratos submetidos a esquemas de intervalo variável (VI) e razão variável (VR).No Experimento 1, os efeitos da introdução de um atraso de 5 s foram comparados à liberação de água independente da resposta (VT). Os resultados do experimento mostraram que, em linha de base (presença de contingência e contigüidade), o esquema VR gerou, relativamente ao VI, taxas de respostas mais elevadas. Com a introdução do atraso de reforço (presença de contingência e contigüidade reduzida) houve diminuição nas taxas de respostas dos sujeitos de ambos os grupos em relação à linha de base, com diminuição maior nas taxas de respostas dos sujeitos do Grupo VI. Na vigência do VT (ausência de contingência, mas não de contigüidade), esta diminuição foi ainda mais acentuada. Os efeitos diferenciados do atraso nos esquemas VI e VR foram detalhados por meio da distribuição de freqüência de respostas no tempo, de modo a se identificarem os valores de atraso que efetivamente ocorreram (isto é, o intervalo entre a liberação do reforço e a última resposta anteriormente emitida). Para os sujeitos do Grupo VI, os valores de atrasos registrados se concentraram geralmente em valores próximos ao atraso programado de 5 s enquanto que, para os sujeitos do Grupo VR, os intervalos efetivamente registrados assumiram valores menores. Uma explicação para esses resultados deve-se às próprias características dos esquemas. Deste modo, a probabilidade dos atrasos registrados se concentrarem no valor do atraso programado é maior no VI do que no VR. No Experimento 2, foi verificado o efeito da introdução de diferentes valores de atraso - 2, 5 e 8 s - sobre a taxa e a distribuição de freqüência de respostas, submetendo-se ratos ingênuos aos esquemas de VI e VR, com e sem atraso de reforço. Os resultados do Experimento 2 mostraram que, com a introdução dos diferentes valores de atraso de reforço (presença de contingência e contigüidade parametricamente manipulada), houve diminuições nas taxas de respostas dos sujeitos de ambos os grupos. A análise por meio da distribuição de freqüência dos valores de atrasos mostrou que para os sujeitos de ambos os grupos - VI e VR, os valores de atrasos registrados assumiram os menores intervalos quando o atraso foi de 2 s, concentraram-se em valores próximos ao atraso programado, quando o atraso foi de 5 s e, foram distribuídos entre os diferentes intervalos quando o atraso foi de 8 s. Resultados diferentes, porém, foram observados em dois sujeitos cujos valores de atrasos se concentraram nos valores de atrasos programados. No conjunto, os resultados de ambos os experimentos mostram que apesar das taxas de respostas semelhantes, identificam-se efeitos do atraso sob a distribuição do responder quando os sujeitos estão sob VI ou VR. Efeitos que não puderam ser observados quando a análise dos dados limitou-se à taxa de resposta, medida esta mais freqüentemente usada na investigação de relações de contingência e contigüidade.The present study comprises two experiments (experiment 1 and experiment 2) that applied delayed reinforcement [non-resentting] procedure [schedule in which the second component operates on a fixed time condition (FT)]. The main purpose was to manipulate experimentally contingencies and contiguity relations by using different reinforcement schedules (response dependent schedule, response dependent schedule with delayed reinforcement and response independent schedule). The experiments investigated the effects of delayed reinforcement imposition on the lever press response rate and distribution of frequency on time, by exposing rats to variable interval (VI) and variable ratio schedule (VR). Experiment 1 compared effects of 5 s delays imposition with response independent water presentation. Experiment 1 showed that VR schedule engendered, in baseline condition (contingency and contiguity condition), higher response rates than did VI schedule. Delayed reinforcement (contingency and reduced contiguity condition) produced lower response rates, in both groups, than that of baseline condition. The lowest rates were observed in VI group. During VT condition (no contingency, but with contiguity), the rate decrease was accentuated. The different effects of delay under VI and VR schedules were showed in detail by the distribution of response frequency on time so that the effective delay values could be identified (the interval between reinforcement presentation and the last emitted response). In VI group, the observed delay values were in general near the programmed 5 s delay, whereas the intervals effectively observed, in VR group, were lower than the programmed 5 s delay. The schedules features can explain these results. The observed delays are more likely to be near the delay programmed value in VI than in VR schedule. Experiment 2 showed the effect of imposition of different delay values 2, 5 and 8 s- on the response rate and frequency distribution, by exposing naïve rats to VI and VR schedules, with and without reinforcement delay. The experiment 2 revealed that the response rates decreased, in both groups, when different reinforcement delay values were presented (contingency and parametrically manipulated contiguity). The analysis of distribution of delay values frequency showed that the registered delay values were lower than the programmed 2 s delay, delay values were in general near the programmed 5 s delay and distributed over the different values in both groups (VI and VR). Different findings were, however, observed in two subjects whose delay values were near the programmed delay values. The results of both experiments, taken together, indicate that the analysis of distribution of delay values frequency reveals the different effects of delay on VI and VR schedule. These effects could not be observed when the data analysis took into account only response rate, a more usual measure employed in investigations on relationship between contingency and contiguity.
47
Lamoureux-Bélair, Guillaume. "L’incidence du rendement sur la gestion du risque au sein de l’industrie des fonds communs de placement." Mémoire, Université de Sherbrooke, 2014. http://hdl.handle.net/11143/5452.
Анотація:
D’un point de vue théorique, la délégation de la gestion au sein de l’industrie des fonds communs de placement présente un conflit d’intérêt important. Les investisseurs désirent maximiser leur rendement ajusté pour leur risque, tandis que les gestionnaires sont davantage motivés par leurs propres intérêts personnels. Le présent mémoire s’intéresse à l’incidence du rendement d’un gestionnaire sur son comportement de prise de risque. Brown al. (1996) font partie des premiers auteurs à étudier ce phénomène, qu’ils appellent l’effet tournoi. L’hypothèse de tournoi amené par ceux-ci stipule que les gestionnaires ayant connu de mauvaises performances relativement aux pairs pendant les six premiers mois d’une année sont tentés d’altérer le risque de leur portefeuille avant la fin de l’année. Leur motivation est de ne pas finir en bas du classement relatif. Notre échantillon est composé de 16 965 fonds communs de placement américains orientés croissance et petites capitalisations croissance, sur la période du 2 janvier 1996 au 31 décembre 2012. Nous testons d’abord l’hypothèse de tournoi dans notre échantillon avec des mesures de risque total et systématique ex post et ex ante, via des tables de contingence et de tests de Friedman (1920). Nous visons ainsi à confronter la littérature qui emploie majoritairement des mesures de risque réalisées, ainsi que des tables de contingence. Nos résultats montrent que le choix de la mesure de risque a une incidence importante sur les conclusions relatives à l’hypothèse de tournoi. Nous exposons par ailleurs que les gestionnaires aux rendements relatifs les plus faibles au cours des six premiers mois de l’année (les perdants) ont l’intention de hausser davantage leur risque total et systématique conditionnel au cours du dernier semestre de l’année, comparativement aux autres gestionnaires (les gagnants). Nous analysons ensuite spécifiquement le comportement des gestionnaires gagnants de fonds communs de placement. Plus précisément, nous vérifions si le risque systématique (résiduel) des fonds communs de placement se rapproche de un (zéro) suite à l’évaluation relative des gestionnaires. À cet effet, nous employons des tests de Friedman (1920) avec deux blocs temporels de deuxième période, à savoir un mois et six mois. Nos résultats exposent bien la dynamique de la prise de risque de ces gestionnaires. En outre, nos conclusions relatives au bloc temporel d’un mois sont davantage significatives et concluantes, en regard à nos hypothèses.
48
Kocáb, Jan. "Statistické usuzování v analýze kategoriálních dat." Master's thesis, Vysoká škola ekonomická v Praze, 2010. http://www.nusl.cz/ntk/nusl-76171.
Анотація:
This thesis introduces statistical methods for categorical data. These methods are especially used in social sciences such as sociology, psychology and political science, but their importance has increased also in medical and technical sciences. In the first part there is mentioned statistical inference for a proportion. Here is written about classical, exact and Bayesian methods for estimating and hypothesis testing. If we have a large sample then we can approximate exact distribution by normal distribution but if we have a small sample cannot use this approximation and it is necessary to use discrete distribution which makes inference more complicated. The second part deals with two categorical variables analysis in contingency tables. Here are explained measures of association for 2 x 2 contingency tables such as difference of proportion and odds ratio and also presented how we can test independence in the case of large sample and small one. If we have small sample we are not allowed to use classical chi-squared tests and it is necessary to use alternative methods. This part contains variety of exact tests of independence and Bayesian approach for the 2 x 2 table too. In the end of this part there is written about a table for two dependent samples and we are interested whether two variables give identical results which occurs when marginal proportions are equal. In the last part there are methods used on data and discussed results.
49
Židanavičiūtė, Jurgita. "Kategorinių požymių priklausomybių struktūros statistinė analizė ir jos taikymas genetikoje." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2010. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2010~D_20100303_113252-41877.
Анотація:
Disertacijoje nagrinėjami kai kurie kategorinių požymių statistinės analizės
uždaviniai – ryšių struktūros bei modelio parinkimo ir jo parametrų įvertinimo
uždaviniai. Disertacijos tikslas – pasiūlyti ryšių struktūros tarp kategorinių
požymių įvertinimo metodą tuo atveju, kai turime didelės dimensijos
duomenų rinkinius ir išsklaidytas dažnių lenteles, t. y. kai daugumoje dažnių
lentelės ląstelių yra mažas stebinių skaičius arba jos yra tuščios. Ši situacija
iliustruojama DNR genetinių sekų statistine analize.
Disertaciją sudaro įvadas, trys pagrindiniai skyriai, išvados, naudotos literatūros
ir autoriaus publikacijų sąrašai.
Įvadiniame skyriuje pristatoma tiriamoji problema ir jos aktualumas, aprašomas
tyrimų objektas, formuluojamas darbo tikslas ir uždaviniai, aptariamas
darbo mokslinis naujumas bei ginamieji teiginiai. Įvado pabaigoje pateikiami
autoriaus pranešimai konferencijose disertacijos tema.
Pirmame skyriuje pateikta kategorinių požymių statistinėje analizėje taikomų
matematinių modelių apžvalga, šių modelių ryšys su Markovo laukų
teorija ir Gibso skirstiniu.
Antrame skyriuje atlikta statistinė analizė kai kurioms realioms DNR sekoms
Markovo eilės jose įvertinimui bei pirminių ir antrinių DNR grandinių
vijų palyginimui: pasiūlyta kategorinių duomenų statistinės analizės metodika,
pagrįsta specialia stebimų duomenų forma, apibendrintu logit modeliu bei
savirankos testais.
Trečiame skyriuje išsklaidytų dažnių lentelės problemai spręsti pasiūlytas
semiparametrinis... [toliau žr. visą tekstą]The dissertation considers some problems in the statistical analysis of categorical variables – the dependence structure between categorical variables and the problems of selecting and assessing the models for this structure. The aim of this dissertation is to propose the method to estimate dependence structure between multivariate categorical variables in case of sparse frequency tables and to apply the proposed method in the statistical analysis of genetic sequences. The thesis layout consists of introduction chapter, three main chapters, conclusions, list of authors’s publications and bibliography chapter. The introduction reveals the investigated problem, importance of the thesis and the object of research and describes the purpose and tasks of the dissertation, research methodology, scientific novelty, the practical significance and defended statements. The introduction end in presenting the author’s publications on the subject of the defended dissertation. In the first chapter of the dissertation various models available for describing the nature of the association between categorical variables are introduced and their link with Markov field theory and Gibbs distribution. In the second chapter the basic notions of DNA sequences and a special structure of genetic data is introduced. The logit models and Markov field theory are applied to assess the dependence structure (interactions) between DNA nucleotides and to test hypothesis about Markov order of these dependencies... [to full text]
50
Židanavičiūtė, Jurgita. "Dependence Structure Analysis of Categorical Variables With Applications in Genetics." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2010. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2010~D_20100303_113305-80061.
Анотація:
The dissertation considers some problems in the statistical analysis of categorical
variables – the dependence structure between categorical variables
and the problems of selecting and assessing the models for this structure. The
aim of this dissertation is to propose the method to estimate dependence structure
between multivariate categorical variables in case of sparse frequency tables
and to apply the proposed method in the statistical analysis of genetic
sequences.
The thesis layout consists of introduction chapter, three main chapters,
conclusions, list of authors’s publications and bibliography chapter.
The introduction reveals the investigated problem, importance of the thesis
and the object of research and describes the purpose and tasks of the dissertation,
research methodology, scientific novelty, the practical significance and
defended statements. The introduction end in presenting the author’s publications
on the subject of the defended dissertation.
In the first chapter of the dissertation various models available for describing
the nature of the association between categorical variables are introduced
and their link with Markov field theory and Gibbs distribution.
In the second chapter the basic notions of DNA sequences and a special
structure of genetic data is introduced. The logit models and Markov field theory
are applied to assess the dependence structure (interactions) between DNA
nucleotides and to test hypothesis about Markov order of these dependencies... [to full text]Disertacijoje nagrinėjami kai kurie kategorinių požymių statistinės analizės uždaviniai – ryšių struktūros bei modelio parinkimo ir jo parametrų įvertinimo uždaviniai. Disertacijos tikslas – pasiūlyti ryšių struktūros tarp kategorinių požymių įvertinimo metodą tuo atveju, kai turime didelės dimensijos duomenų rinkinius ir išsklaidytas dažnių lenteles, t. y. kai daugumoje dažnių lentelės ląstelių yra mažas stebinių skaičius arba jos yra tuščios. Ši situacija iliustruojama DNR genetinių sekų statistine analize. Disertaciją sudaro įvadas, trys pagrindiniai skyriai, išvados, naudotos literatūros ir autoriaus publikacijų sąrašai. Įvadiniame skyriuje pristatoma tiriamoji problema ir jos aktualumas, aprašomas tyrimų objektas, formuluojamas darbo tikslas ir uždaviniai, aptariamas darbo mokslinis naujumas bei ginamieji teiginiai. Įvado pabaigoje pateikiami autoriaus pranešimai konferencijose disertacijos tema. Pirmame skyriuje pateikta kategorinių požymių statistinėje analizėje taikomų matematinių modelių apžvalga, šių modelių ryšys su Markovo laukų teorija ir Gibso skirstiniu. Antrame skyriuje atlikta statistinė analizė kai kurioms realioms DNR sekoms Markovo eilės jose įvertinimui bei pirminių ir antrinių DNR grandinių vijų palyginimui: pasiūlyta kategorinių duomenų statistinės analizės metodika, pagrįsta specialia stebimų duomenų forma, apibendrintu logit modeliu bei savirankos testais. Trečiame skyriuje išsklaidytų dažnių lentelės problemai spręsti pasiūlytas semiparametrinis... [toliau žr. visą tekstą]